Fire a tag just once per session: Without using Cookie (GTM)

Google Tag Manager provides three basic, tag firing options i.e., Unlimited, Once per Event and Once per page. However, there isn’t yet an option to fire a tag ‘just once per session‘ or ‘Only on first pageview‘.

When I tried searching for this, I could find few solution. However, the problem is that they all involve creating ‘cookies‘ to fire a tag just once per session.

Find below the best “Cookie” based working solutions to fire a tag only once per session/visit:

• How to set tag in GTM to fire only once per session? – Has an idea
• Fire a tag only on the first page view with Google Tag Manager – Analyticsmania
• UA: Fire a script just once per session – Simoahava
• Github import – FOnce – Involves creating a first party cookie

First party cookies are not a problem yet. However, I’m avoiding relying on cookies because of all the hype around future ‘cookie-less world‘.

Besides, why use cookies when there is much simpler, quicker and easier way to fire tag once per session or visit? 🤔

Session Storage Vs Cookie

Isn’t it better to use ‘sessionStorage‘ than ‘Cookie‘ for this particular purpose? Avoiding Cookie in this particular use-case has multiple pros and we can still fire a tag only on the first page view using google tag manager as shown below.

Remember: There is usually more than one ways to solve a problem. You can even use dataLayer and events to fire a tag just once. However, that requires some development effort too. 😀

Here is a gist of logic to fire a tag only once per session:

• Create an item in the Session-Storage Object on first pageview.
• Increment it on subsequent pageviews.
• Check the value of session storage.
  • If it is < 2, then and only then fire the tag.

An extended version of this use-case. Like keeping a local count of pageviews on client machine — (or) Firing a tag on N^th pageview can be found here. For Example: – Firing a tag on 4th Pageview. (really engaged visitors?)

Step 0: Understanding the code to fire tag once per session

Let’s first understand the code to set and check sessionStorage item that helps to fire tag only once per session.

Since it’s very basic and simple, just the comments in the code block should suffice. Follow the instructions below the code to see it in action via your GTM container.

var pv = 1;
//check if sessionStorage item exisits
//If it does, increment it.
if (sessionStorage.pv) {
    pv = pv + 1;
    sessionStorage.setItem("pv", pv);
}
//If it doesn't, create it!
else if (!sessionStorage.pv) {

    sessionStorage.setItem("pv", pv);

}

That’s it. So simple right? If you observe closely, this basic block, when executed on every pageview won’t increment ‘pv’ beyond 2. If you want to keep count of the actual pageviews of every visitor, you would simply avoid resetting it. Head to this article to see how to create a pageview counter and fire tag anywhere in the user-journey.

Step 1: Create a GTM tag to fire this on page view.

Choose ‘Custom HTML’ type. Set it to fire on all page view.

Step 2: Create a variable to read and return this value from sessionStorage.

Type: Custom JavaScript.

Code: See Below

function(){

//convert the value to integer for easy comparision.
return parseInt(window.sessionStorage.pv);
}

Step 3: Create the trigger/condition to fire a tag only once per session

That’s it. You’re all set!

Note that you can use this technique on any tag management platform that doesn’t have a built-in way to achieve this.

Does it work? – Test it.

Feel free to leave your thoughts, comments or concerns below.

If you’re new to Tag management and Google Tag Manager, read this post to quickly get an idea of implementing Google analytics.